A novel approach to predict green density by high-velocity compaction based on the materials informatics method

High-velocity compaction is an advanced compaction technique to obtain high-density compacts at a compaction velocity of ≤10 m/s. It was applied to various metallic powders and was verified to achieve a density greater than 7.5 g/cm^3 for the Fe-based powders. The ability to rapidly and accurately predict the green density of compacts is important, especially as an alternative to costly and time-consuming materials design by trial and error. In this paper, we propose a machine-learning approach based on materials informatics to predict the green density of compacts using relevant material descriptors, including chemical composition, powder properties, and compaction energy. We investigated four models using an experimental dataset for appropriate model selection and found the multilayer perceptron model worked well, providing distinguished prediction performance, with a high correlation coefficient and low error values. Applying this model, we predicted the green density of nine materials on the basis of specific processing parameters. The predicted green density agreed very well with the experimental results for each material, with an inaccuracy less than 2%. The prediction accuracy of the developed method was thus confirmed by comparison with experimental results.

Usefulness of Positron Emission Tomography in Patients with Syphilis： A Systematic Review of Observational Studies

Background： Diagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography （PET） in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis. Methods： We searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases （SinoMed, Wanfang, and CNKI） for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms ＂syphilis＂ and ＂positron emission tomography＂. We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans. Results： Of 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ~ 12.1 years. In primary syphilis, increased fluorodeoxyglucose （FDG） accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary＇ syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the asymmetry of radiotracer uptake. Conclusion： PET is helpful in targeting diagnostic interventions, characterizing disease extent, assessing nodal involvement, and treatment efficacy for syphilis.